The application generally relates to antenna systems, and in particular, a reconfigurable microwave fluidic shutter for selectively shielding an antenna array.
Active array antenna technologies for space, airborne, and ground systems are in wide use including multi-layered panel arrays using thin lightweight and conformal active array antennas for airborne platforms. Active array antennas for platforms such as unmanned airborne vehicles (UAVs) require increased reconfigurability to enhance performance, tunable frequency bandwidth, polarization, and signature. Typically, this may be accomplished with diode switches and mechanical actuators which increase power consumption and reduce reliability, respectively.
FIG. 1A illustrates a conventional active antenna array assembly 100. Assembly 100 generally include array antenna 110 having array antenna radio frequency (RF) feed 112, array of antenna radiating elements 114, and input/output 116. Assembly 100 also includes protective enclosure (also known as a radome) 120. Radomes are designed to be transparent to RF signals received and/or reflected by the antenna. Radome 120 can be designed as a solid sheet of dielectric material.
Radome 120 is structurally configured to protect the antenna surfaces from the environment (e.g., wind, rain, ice, sand, ultraviolet light, etc.). Radome 120 may be generally formed of a dielectric material that is transparent to received electromagnetic signals 130 or transmitted and/or reflected signals 140 by antenna array 112. FIG. 1B illustrates a similar active antenna array assembly 100′, but having a curved array antenna 110′ and curved radome 120′. As shown, radome 120′ may be formed of a solid sheet of dietetic material.
FIG. 2A illustrates another conventional active antenna array assembly 200. Radome 220 is constructed of multiple dielectric layers 222, 224. Dielectric sheets 222, 224 may be fused together to form thin cavity 226 therebetween which is filled with air. While two dielectric layers 222, 224 are shown, additional layers may also be conventionally provided so as to define multiple spaces. FIG. 2B illustrates a similar conventional active antenna array assembly 200′, but having a curve array antenna 210′ and a curved radome 220′.
Typically, a metal cover (not shown) may be placed over the radome or sandwiched between the two dielectrics to prevent outside RF signal from entering the antenna and reflecting off the antenna when the antenna is not in operation. The metal cover is removed when the antenna is ready to operate. This process may be performed manually and thus, is not efficiently performed. On the other hand, if this process is automated, it cannot be easily be (re)configured for various operations.